class_docstr: test GridspecLayout
code: def test_setitem_index(self):
      box = widgets.GridspecLayout(2, 3)
      button1 = widgets.Button()
      button2 = widgets.Button()
      button3 = widgets.Button()
      button4 = widgets.Button()
  
      box[0, 0] = button1
      button1_label = button1.layout.grid_area
      assert button1 in box.children
      assert (
          box.layout.grid_template_areas
          == '''"{} . ."\n". . ."'''.format(button1_label)
      )
  
      box[-1, -1] = button2
      button2_label = button2.layout.grid_area
      assert button1_label != button2_label
      assert button2 in box.children
      assert (
          box.layout.grid_template_areas
          == '''"{} . ."\n". . {}"'''.format(
              button1_label, button2_label
          )
      )
  
      box[1, 0] = button3
      button3_label = button3.layout.grid_area
      assert button1_label != button3_label
      assert button2_label != button3_label
      assert button3 in box.children
      assert (
          box.layout.grid_template_areas
          == '''"{b1} . ."\n"{b3} . {b2}"'''.format(
              b1=button1_label, b2=button2_label, b3=button3_label
          )
      )
  
      # replace widget
      box[1, 0] = button4
      button4_label = button4.layout.grid_area
      assert button1_label != button4_label
      assert button2_label != button4_label
      assert button4 in box.children
      assert button3 not in box.children
  
      assert (
          box.layout.grid_template_areas
          == '''"{b1} . ."\n"{b4} . {b2}"'''.format(
              b1=button1_label, b2=button2_label, b4=button4_label
          )
      )
  
imports: from unittest import TestCase
  from unittest import mock
  import pytest
  import traitlets
  import ipywidgets
  from ipywidgets.widgets.widget_templates import LayoutProperties
label_desc: Use image node_id 2 for calling the TestGridspecLayout obj's underlying member method code with example usage: obj.test_setitem_index() without return types